There is a clutch control device known in the related art that executes hydraulic control on a plurality of hydraulic clutches built into a transmission in a work vehicle (see patent reference literature 1).
The clutch control device disclosed in patent reference literature 1 executes variable control on a control parameter (gradual hydraulic pressure increase rate) used in the hydraulic control of a hydraulic clutch (secondary clutch) to shift from a released state to an engaged state based upon three speed-change conditions, i.e., the extent to which the accelerator is operated, the brake engagement state and the speed at the time of the speed change. A hydraulic value based upon which a hydraulic pressure is to be applied quickly to the secondary clutch must be set as another control parameter, and this hydraulic value is determined through arithmetic operation executed based upon the torque output and the like from a torque converter at the time of the speed change. The clutch control device in the related art, which controls the secondary clutch based upon the gradual hydraulic pressure increase rate and the hydraulic value at the time of the speed change as described above, is designed to minimize the extent of speed change shock.    Patent reference literature 1: Japanese Patent No. 2732096